Hydrorefining catalyst containing diimino molybdenum chloride and certain complexes thereof



United States Patent 3,288,722 HYDROREFINENG CATALYST CONTAINING DHMINO MOLYBDENUIH CHLORIDE AND CERTAEN COMPLEXES THEREGF William K. T. Gleim, Island Lake, 11]., assignor to Universal Oil Products (Iompauy, Des Plaines, 111., a corporation of Delaware No Drawing. Fiied Dec. 28, 1964, Ser. No. 421,723 6 Claims. (Cl. 252438) The invention described herein is adaptable to a process for the hydrorefining of heavy hydrocarbon fractions and/or distillates. More specifically, the present invention is directed toward a novel catalytic composite for particular utilization in treating petroleum crude oils and topped, or reduced crude oils for the primary purpose of removing organo-metallic contaminants, while simultaneously converting pentane-insoluble asphaltenic material into soluble, normally liquid hydrocarbons.

Petroleum crude oils, and topped or reduced crude oils, as well as other heavy hydrocarbon fractions and/ or distillates, including black oils, heavy cycle stocks, vis: breaker liquid effluent, crude tower bottoms product, tar sand oils, etc., are contaminated by the inclusion of excessive quantities of various non-metallic and metallic impurities which detrimentally afiect various processes to which such heavy hydrocarbon mixtures may be subjected. Among the non-metallic impurities are nitrogen, sulfur and oxygen which exist as heteroatomic compounds, nitrogen probably being most undesirable because it effectively poisons various catalytic composites which may be employed in the conversion of petroleum fractions. Both nitrogenous and sulfurous compounds are objectionable because combustion of fuels containing these impurities results in the release of nitrous and sulfur oxides which are noxious, corrosive, and present, therefore, a serious problem with respect to pollution of the atmosphere. With respect to motor fuels, sulfur and sulfurous compounds are particularly objectionable because of odor, gum and varnish formation, and significantly decreased lead susceptibility.

In addition to the foregoing described contaminating influences, petroleum crude oils and other heavy hydrocarbon-aceous material contain high molecular weight asphaltenic compounds. These are non-distillable, oilinsoluble coke precursors which often are found to contain sulfur, nitrogen, oxygen and various metals. Of the metallic contaminants, those containing nickel and vanadium are most common although other metals including iron, copper, lead, zinc, etc. are often present. Although the metallic contaminants may exist within the hydrocarbonaceous material in a variety of forms, they are generally found as organo-metallic compounds of relatively high molecular weight, including metallic porphyrins and the various derivatives thereof. A significant quantity of the organo-metallic complexes are linked with asphaltenic material and become concentrated in the residual fraction; other organo-metallic complexes are volatile, oil-soluble, and are, therefore, present in the lighter distillate fraction. A reduction in the concentration of the organo-metallic complexes is not easily achieved, and to the extent that the crude oil, reduced crude oil, or other heavy hydrocarbon charge stock derived therefrom, becomes suitable for further processing. Notwithstanding that the concentration of these organo-metallic complexes may be relatively small, as in a lighter distillate fraction, for example often less than about 10 p.p.m., calculated as if the complex existed as the elemental metal, subsequent processing techniques are adversely affected thereby. With respect to a process for hydrorefining or treating of hydrocarbon fractions and/or distillates, the presence of large quantities of asphaltenic material and organo-rnetallic compounds interferes considerably with the activity of the catalyst in effecting the destructive removal of the nitrogenous, sulfurous and oxygenated compounds, which function is normally the easiest for the catalytic composite to perform to an acceptable degree. Therefore, it is highly desirable to produce a hydrocarbon mixture substantially free from asphaltenic material and organo-metallic compounds, and which is substantially reduced in nitrogen and sulfur concentration.

A wide variety of heavy hydrocarbon fractions and/ or distillates may be treated, or decontaminated effectively through the utilization of the catalytic composite of the present invention. Such heavy hydrocarbon fractions include full boiling range crude oils, topped or reduced crude oils, atmospheric distillates, vis: breaker bottoms product, heavy cycle stocks from thermally or catalytically-cracked charge stocks, heavy vacuum gas oils, tar sand oils, etc. Such heavy hydrocarbonaceous material includes a Wyoming sour crude oil, having a gravity of 23.2 API at 60 F., and contaminated by the presence of 2.8% by weight of sulfur, 2,700 p.p.m. of total nitrogen, approximately 100 p.p.m. of metallic complexes, computed as the elemental metals, having a high boiling, pentane-insoluble asphaltenic fraction in an amount of about 8.4% by weight. A more difficult charge stock to convert into useful liquid hydrocarbons, is a crude tower bottoms product having a gravity, API at 60 F., of 14.3, and contaminatedby the presence of 3.0% by weight of sulfur, 3,830 p.p.m. of total nitrogen, p.p.m. of total metals and about 10.93% by weight of asphaltenic compounds. Similarly, an atmospheric tower bottoms product, having a gravity of 7.0 API at 60 F., is contaminated by 6,060 p.p.m. of total nitrogen, 4.05% by weight of sulfur, more than 450 p.p.m. of total metals, and contains an asphaltenic fraction in an amount of 24.0% by weight. As herein'oefore stated, asphaltenic material is a high molecular weight hydrocarbon mixture having the tendency to become immediately deposited within the reaction zone and other process equipment, and onto the catalytic composite in the form of a high molecular weight residue. Furthermore, the presence of excessive quantities of asphaltenes, in addition to the foregoing described contaminating influences, appears to inhibit the activity of the catalyst in regard to the destructive removal of sulfur and nitrogen.

The object of the present invention is to provide a catalytic composite suitable for use in a process for hydrorefining heavy hydrocarbonaceous material, and particularly full boiling range crude oils, and topped or reduced crude oils. The use of the catalyst of the present invention affords the utilization of either a fixed-bed or a fixed fluidized hydrorefining process, or a slurrytype pnocess in which the catalytic composite and change stock are intimately admixed. Heretofore, the fixed-bed hydrorefinin g process has not :been considered feasible due to the deposition of coke and other gummy carbonaceous material within the reaction zone. Although the difiiculties encountered in a fixed-bed catalytic process are at least partially solved by a moving bed or slurrytype operation, wherein the finely-divided catalytic composite is intimately admixed with the hydrocarbon charge stock, the mixture being subjected to the desired operating conditions, there exists the disadvantage of having a relatively small amount of catalyst being admixed with relatively large quantities of asphaltenic material. In other words, too few catalytically active sites are made available for immediate reaction, with the result that the asphaltenic material has the tendency to undergo thermal cracking, resulting in the production 'Otf large quantities of light gases and coke. These diffculties are in turn partially avoided through the utilization of a fixedfluidized process in which the catalytic composite is disposed within a confined reaction zone, being maintained, however, in a fluidized state by exceedingly lange quantities of a fast-flowing hydnogencontaining gas stream.

The crude oil hydrorefining catalyst of the present invention permits effecting the process in a fixeds'bed unit without incurring the difliculties hereinbefore described. Furthermore, the catalyst, when unsupported, permits an efficient utilization of a slurry-type process. When combined with a suitable refractory inorganic oxide carrier material, the catalyst hereinafter described also permits the economic utilization of a fixed-fluidized :bed process. In any event, the catalyst of the present invention is especially advantageous in effecting the removal of onganometallic compounds while simultaneously converting pentane-insolu'ble material into pen tane-solu ble liquid hydrocarbons, and effecting the destructive removal of significantly large quantities of sulfuro us and nitrogenous compounds.

In a :broad embodiment, the present invention relates to a hydr-orefining catalyst comprising a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof.

In another embodiment, the present invention encompasses a hydrorefining catalyst comprising a transitional metal complex of diimino molybdenum chloride having the folowing structural formula:

ClMo\ /Me and wherein Me is a metal from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese.

As hereinbefore set forth, the catalyst may be combined with a suitable carrier material for utilization in a fixed bed process for the hydrorefining of petroleum crude oils. Therefore, the present invention also involves a hydroretining catalyst comprising a composite of silica and from about 12.0% to about 88.0% by weight of alumina, combined with from about 5.0% to about 30.0% by weight of a transitional metal complex of diimino molybdenum chloride having the following structural formula:

a ClMo Me MoCl a N, N

and wherein Me is a metal selected from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese.

The fixed-bed process, for which the catalyst of the present invention is particularly adaptable, is effected by reacting the hydrocanbon' change stock, such as a petroleum crude oil containing pentane-inscluble asphaltenes, with hydrogen, in the presence of from about 1.0% to about 15.0% of hydrogen sulfide, and in con-tact with a catalytic composite of silica and 12.0% to about 88.0% by weight of alumina, combined with a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof having the rfollowing structural formula:

The hydrorefining conditions include a temperature within the range of about 225 C. to about 500 C. and

a pressure above about 500 p.s.i.g., having an upper limit of about 5,000 p.s.i.g.

From the foregoing embodiments, it will be noted that the catalyst of the present invention is selected from a particular group of molybdenum compounds. This particular group comprises diimino molybdenum chloride having the following structural formula:

ClMo

NH The remainder of the group of molybdenum compounds, from which the catalyst of the present invention is derived, constitutes transitional metal complexes of diimino molybdenum chloride. These transitional metal complexes have the following structural formula:

The transitional metals, designated in the foregoing structural formula by Me, are selected from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese. When utilized in a slurry-type process, the catalyst, for example the nickel complex of diimino molybdenum chloride, is admixed with the charge stock in an amount of from about 5.0% to about 30.0% by Weight thereof. It is preferred to utilize the complex as a finely-divided, talc-like powder, being added to the crude oil in suitable incremental portions of the total amount, accompanied by agitation. In this manner, the colloidally dispersed catalyst is suspended within the charge stock virtually immediately upon the addition thereto. The slurry-type process, utilizing the catalyst of the present invention, may be concluded in a batch-type manner or in an enclosed vessel through which the colloidal suspension is passed; when carried out in a continuous manner, the process may be conducted in either upward flow or downward flow. The normally liquid hydrocarbons are separated from the total reaction zone effluent by any suitable means, for example, through the use of a centrifuge or settling tank, at least a portion of the remaining catalyst-containing sludge being combined with the fresh petroleum crude oil and recycled to the reaction zone. In order to maintain the highest possible degree of activity, it is preferred that at least a portion of the catalyst-containing sludge be removed from the process prior to combining the remainder with fresh crude oil. The precise quantity of catalyst-containing sludge removed from the process will be dependent upon the desired degree of contaminant removal. It is further desirable to add a quantity of the molybdenum compound to the petroleum crude oil in order to compensate for that quantity removed with the catalyst-containing sludge.

When intended for use in a fixed-bed, or fixed-fluidized process, the molybdenum compound is combined with a suitable refractory inorganic oxide carrier material. Although the precise composition and method of manufacturing the carrier material is not considered a limiting feature of the present invention, the preferred carrier material, in order to have the most advantageous physical and chemical structure, will contain at least a portion of alumina and have an apparent bulk density less than about 0.35 grams/ cc. The preferred catalytic composite comprises a carrier material of silica and from about 12.0% to about 88.0% by weight of alumina. In many instances, however, other refractory inorganic oxides may be employed in conjunction with the alumina, and include zirconia, magnesia, titania, boria, strontia, hafnia, and mixtures of two or more. By way of specific examples, a satisfactory carrier material may comprise equimolar quantities of alumina and silica, or 63.0% by weight of alumina and 37.0% by weight of silica, or a carrier of 68.0% by weight of alumina, 10.0% by Weight of silica and 22.0% by weight of boron phosphate. The carrier material may be formed by any of the numerous techniques which are rather well defined in the prior art. Such techniques include the acid-treating of a natural clay, sand or earth, co-precipitation, or successive precipitation from hydrosols, and which techniques are frequently coupled with one or more activating treatments including hot oil aging, steaming, drying, oxidizing, reducing, calcining, etc. The pore structure of the carrier material, commonly defined in terms of surface area, pore diameter and pore volume, may be developed to specified limits by any means including aging the hydrosol and/or hydrogel under controlled acidic or basic conditions, or by gelling the carrier at a critical pH, or by treating the carrier with various inorganic or organic reagents.

The catalyst is prepared by initially forming an aluminacontaining refractory inorganic oxide carrier material having the foregoing described characteristics. For example, an alumina-silica composite containing about 63.0% by weight of alumina is prepared by the co-precipitation of the respective hydrosols. The precipitated material, generally in the form of a hydrogel, is dried at a temperature of about 100 C. and for a time sufiiciently long to remove substantially all of the physically-held water. The composite is then subjected to a high-temperature calcination technique, in an atmosphere of air, for a period of about one hour at a temperature above about 300 C., which technique serves to remove the greater proportion of the chemically-bound water. The calcined carrier material is then impregnated with gaseous molybdenum chloride (MoCl in a suitable inert atrnos phere such as nitrogen. The thus impregnated carrier is treated with ammonia and calcined in an inert atmosphere at a temperature of about 300 C. to convert the molybdenum chloride to diimino molybdenum chloride. Where it is desired to employ a transitional metal complex of the diimino molybdenum chloride, the ammoniatreated and calcined composite is next impregnated with a salt of the selected transitional metal dissolved in a suitable organic solvent including alcohols, esters, ketones, aromatic hydrocarbons, etc. The salt of the transitional metal is employed in an amount of one metal atom to two mols of diimino molybdenum chloride, and suflicient to result in a final coposite containing about 5.0% to about 30.0% by weight of the transitional metal complex. The impregnated alumina-containing composite is dried at a temperature less than about 150 C., preferably within the range of about 100 C. to about 150 C., and then calcined at a temperature of from 500 C. to 600 C.

The fixed-bed hydrorefining process, utilizing the catalyst prepared in accordance with the method of the present invention, may be effected by initially admixing the hydrocarbon charge stock with hydrogen in an amount within the range of from about 5,000 to about 50,000 s.c.f./bbl. of liquid hydrocarbons. The mixture is heated to a temperature of from about 225 C. to about 500 C., and passes into the reaction zone maintained under an imposed pressure within the range of about 500 to about 5,000 pounds per square inch. The hydrocarbon charge stock contacts the fixed-bed of catalyst at a liquid hourly space velocity (defined as volumes of liquid hydrocarbon charge per hour per volume of catalyst disposed within the reaction zone) of from about 0.5 to about 5.0. It is preferred that the reaction zone atmosphere comprises hydrogen sulfide which has been added with the hydrogen-containing gas stream, as distinguished from that which may be produced by the hydrogenation/ hydrocracking reactions. That is, the beneficial effects of added hydrogen sulfide appear to occur only when the latter is present at the time the hydrogenation reactions are being initiated. The hydrogen sulfide is added to the hydrogen atmosphere in an amount of from about 1.0 to about 15.0 mol percent. The precise operating conditions, including temperature and pressure, are at least partially dependent upon the physical and chemical characteristics of the hydrocarbon charge stock, the length of about one hour at a temperature of about 550 C of the period during which the catalyst has been functioning, and the desired end result. It is understood that the operating conditions, under which the catalytic composite of the present invention is employed, are not limiting upon the scope of the appended claims. The following examples are given for the purpose of illustrating the method by which the catalyst of the present invention is prepared, and the benefits afiorder the hydrorefining of heavy hydrocarbonaceous material through the utilization thereof. The charge stocks, temperatures, pressures, catalysts, rates, etc., are herein presented as being exemplary only, and are not intended to limit the present invention to an extent greater than that defined by the scope and spirit of the appended claims.

Example I The charge stock employed in illustrating the fixedbed hydrorefining process, utilizing the catalyst of the present invention, is a topped Wyoming sour crude oil. 'The natural crude oil, having a gravity of 232 API at 60 F., is contaminated by the presence of 2.8% by weight of sulfur, approximately 2,700 ppm. of total nitrogen, ppm. of metallic porphyrins (computed as if the metallic component existed as elemental nickel and vanadium), and comprises a high-boiling, pentane-insoluble asphaltenic fraction in an amount of about 8.39% by Weight of the total crude oil. The topped crude oil indicates agravity, API at 60 F., of 19.5, and contains 3.0% by Weight of sulfur, about 2,900 p.p.m. of total nitrogen, ppm. of nickel and vanadium, the pentane-insoluble asphaltenic fraction being about 8.5% by weight.

The catalytic composite is a spray-dried alumina-silica carrier material containing about 63.0% by weight of alumina on a dried basis. The spray-dried composite is oxidized or calcined in an atmosphere of air for a period The calcined alumina-silica composite, at a temperature below 265 C., is impregnated with vaporous molybdenum pentachloride in admixture with nitrogen. Without increasing the temperature, the molybdenum pentachloride impregnated composite is treated with ammonia and calcined in nitrogen at a temperature of 300 C., to produce the dimino molybdenum chloride within the composite. An iso-amyl alcohol solution of platinum tetrachloride is used in an impregnating technique to form the platinum complex of diimino molybdenum chloride within the composite, and in an amount such that the final composite, after calcination at a temperature of 550 C., contains about 15.0% by weight of said complex. The calcined composite, having a particle size ranging from about 20 to microns, is disposed as a fixed-bed in a reaction zone in an amount of about 200 grams. The temperature of the catalyst is increased to a level of about 400 C., and hydrogen is admixed with the previously described topped Wyoming sour crude oil, in an amount of about 25,000 s.c.f./bbl. of liquid charge, a compressor being utilized to maintain the pressure within the reaction zone at about 1,500 pounds per square inch.

The reaction products from the reaction zone are continuously cooled and passed into a high-pressure separator from which a liquid hydrocarbon product is removed to a receiver, the hydrogen-rich gas stream being removed through a water scrubber and recycled to the reactor. In order to compensate for the quantity of hydrogen consumed within the process, and absorbed in the normally liquid product effluent, fresh hydrogen is added to the recycle gas stream as determined by the operating pressure within the reaction zone, in this instance being in an amount of about 2,000 s.c.f./bbl. For approximately one-half of its effective, acceptable life, the catalytic composite will promote the hydrogenation/hydrocracking reactions required to produce a normally liquid product substantially free from pentane-insoluble' asphaltenes, organo-metallic contaminants and sulfurous and nitrogenous compounds. Thus, the normally liquid product efiiuent will contain less than about 0.5% by weight of pentane-insoluble asphaltenic material, less than about 0.5 p.p.m. of organo-metallic compounds, less than 50 p.p.m. of total nitrogen, and less than about 0.10% by weight of sulfur, the gravity thereof, API at 60 F., being within the range of about 30.0 to about 32.0.

As hereinbefore set forth, the presence of excessive quantities of pentane-insoluble asphaltenes as well as the organo-metallic compounds, interferes considerably with the cap-ability of the catalyst to efiect the destructive removal of nitrogenous and sulfurous compounds. T herefore, the catalyst will indicate a normal activity decline through an increase in the concentration of residual sulfurous and nitrogenous compounds in the normally liquid product efiluent. However, since the pentane-insoluble asphaltenes and organo-metallic compounds will be below the previously stated limits of 0.5% by weight and 0.5 p.p.m; respectively, the operation'may be continued on an economic basis notwithstanding a comparatively high concentration of residual nitrogenous and sulfurous compounds. In this situation, the normally liquid product effluent is subjected to a second stage operation at significantly more severe conditions for the purpose of effecting the complete destructive removal of the remaining sulfurous and nitrogenous compounds.

Example I] Dimino molybdenum chloride, in an amount of about 20.0 grams,'and in the form of talc-like powder, is added to 200 grams of the Wyoming sour crude oil hereinabove described. The resulting mixture is placed in an 850 cc. rocker-type autoclave, pressured to atmospheres with hydrogen sulfide, then to 100 atmospheres with hydrogen, and slowly heated to a temperature of about 400 0, resulting in a final pressure of about 220 atmospheres; these conditions are maintained for a period of about 8 hours. The autoclave is permitted to cool, and depressured to atmospheric conditions; the normally liquid product efiluent indicates a gravity, API at 60 F., of 32.6. Analyses indicate that the liquid hydrocarbon fraction is contaminated by only about 150 p.p.m. of nitrogen, 0.20% by weight of sulfur and only about 0.04% by weight of pentane-insoluble asphaltenes. The analyses further show that the concentration of organometallic porphyrins is less than about 0.5 p.p.m.

The foregoing specification and examples clearly indicate the benefits afforded a process for hydrorefining petroleum crude oil, and other heavy hydrocarbonaceous material, through the use of the catalyst of the present invention. The contaminating influences have been removed to the extent required for further processing, without incurring the deleterious effects otherwise resulting.

I claim as my invention:

1. A hydrorefining catalyst comprising diimino molybdenum chloride.

2. A hydrorefining catalyst comprising a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex of diimino molybdenum chloride having the following structural formula:

and wherein Me is a metal selected from the group consisting of iron, cobalt, nickel, platinum palladium, ruthenium, rhodium and manganese.

5. A hydrorefining catalyst comprising alumina, silica and from about 5.0% to about 30.0% of a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof having the following structural formula:

Me /MOC1 N ClMo and wherein Me is a metal selected from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese.

6. A hydrorefining catalyst comprising a composite of silica and from about 12.0% to about 88.0% by weight of alumina, combined with from about 5.0% to about 30.0% by weight of a transitional metal complex of diimino molybdenum chloride having the following structural formula:

and wherein Me is a metal selected from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese.

References Cited by the Examiner J. W. Mellor, Comprehensive Treatise on Inorg. and Theo. Chem., vol. 22, p. 625 (-1930).

OSCAR R. VERTIZ, Primary Examiner. A. GREIF, Assistant Examiner. 

2. AHYDROREFINING CATALYST COMPRISING A MOLYBDENUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF DIIMINO MOLYBDENUM CHLORIDE AND A TRANSITIONAL METAL COMPLEX OF DIIMINO MOLYBDENUM CHLORIDE HAVING THE FOLLOWING STRUCTURAL FORMULA: 